title: Changes in functional integration with the non-epileptic temporal lobe of patients with unilateral mesiotemporal epilepsy.
abstract: OBJECTIVE
  To investigate epilepsy-induced changes in effective connectivity between the non-epileptic amygdalo-hippocampal complex (AHC) and the rest of the brain in patients with unilateral mesiotemporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS).
  
  
  METHODS
  Thirty-three patients with unilateral MTLE associated with HS (20 females, mean age: 36 years, 19 left HS) and 33 adult controls matched for age and gender underwent (18)F-Fluorodeoxyglucose positron emission tomography (FDG-PET). Right-HS patients' FDG-PET data were flipped to obtain a left-epileptic-focus-lateralized group of patients. Voxels of interest (VOI) were selected within the cytoarchitectonic probabilistic maps of the non-epileptic AHC (probability level  = 100%, SPM8 Anatomy toolbox v1.7). Patients and controls were compared using VOI metabolic activity as covariate of interest to search for epilepsy-induced changes in the contribution of the non-epileptic AHC to the level of metabolic activity in other brain areas. Age, gender, duration of epilepsy, seizure type and frequency were used as covariates of no-interest for connectivity analyses.
  
  
  RESULTS
  Significant decrease in effective connectivity was found between the non-epileptic AHC and ventral prefrontal cortical areas bilaterally, as well as with the temporal pole and the posterior cingulate cortex contralateral to HS. Significant increase in connectivity was found between the non-epileptic AHC and midline structures, such as the anterior cingulate and dorsal medial prefrontal cortices, as well as the temporo-parietal junction bilaterally. Connectivity analyses also revealed a preserved positive connectivity between the non-epileptic and the epileptic AHC in the patients' group.
  
  
  CONCLUSIONS
  This study evidences epilepsy-induced changes in connectivity between the non-epileptic AHC and some limbic and default mode network areas. These changes in connectivity probably account for emotional, cognitive and decision-making impairments frequently observed in MTLE patients. The preserved neurometabolic connectivity between the non-epileptic and the epileptic AHC in MTLE patients is pivotal to explain the epilepsy-induced changes found in this study.
authors.affiliation: Laboratoire de Cartographie fonctionnelle du Cerveau, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium. ntrotta@ulb.ac.be
authors.forename: Nicola
authors.initials: N
authors.lastname: Trotta
authors.forename: Serge
authors.initials: S
authors.lastname: Goldman
authors.forename: Benjamin
authors.initials: B
authors.lastname: Legros
authors.forename: Kristof
authors.initials: K
authors.lastname: Baete
authors.forename: Koen
authors.initials: K
authors.lastname: Van Laere
authors.forename: Patrick
authors.initials: P
authors.lastname: Van Bogaert
authors.forename: Xavier
authors.initials: X
authors.lastname: De Tiège
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D004833:Epilepsy, Temporal Lobe / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D012044:Regression Analysis; D012598:Sclerosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D013702:Temporal Lobe / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18